IBKR's option Expiration Exposure monitoring can liquidate positions based upon certain expiration or corporate action related events which, after giving effect to, would create undue risk and/or operational concerns. The Post Expiry Excess (Predicted) amount in the Account Window is calculated using the projected maintenance requirements of the positions predicted to be in the account after expiration. If the Post Expiry Excess (Predicted) number is positive, then the account is projected to be margin compliant after the expiration. If the Post Expiry Excess (Predicted) number is negative, then the account is projected to be in a maintenance margin deficit after expiration.
To determine if an expiring option is In-the-Money or Out-of-the-Money the Options Clearing Corp. uses the (CC) Composite Close price of the underlying that includes reported Last Sales from all reporting Exchanges and Market Centers. IBKR’s Expiration Exposure adds a fraction of 1% to the current Mark Price of the underlying while the option is still trading to project if that option will finish In-the-Money or Out-of-the Money because the calculated Composite Close price at the end of the Regular Trading Hours session can be different than any individual reported Last Sale for the underlying. Accounts that hold options expiring on that day need to actively monitor the account's real time margin compliance and the "Post Expiry Excess (predicted)" value. On an option's Last Trade date, IBKR can liquidate positions during the last 2.5 hours if the account is projected to be in a maintenance margin deficit after any expiring options stop trading.